Vision in macular degeneration patients

ABSTRACT

An eyeglass lens and manufacturing method using a variable refractive index material, such as epoxy. In one embodiment, a method of making an eyeglass lens includes: imaging a patient&#39;s eye to determine a wavefront prescription for the patient; and curing the lens based on the wavefront prescription such that the wavefront guided lens corrects for aberrations over the lens for a plurality of gazing angles of the patient.

RELATED APPLICATION INFORMATION

This application is a continuation of U.S. patent application Ser. No.11/703,855, filed on Feb. 7, 2007, which is a continuation of U.S.patent application Ser. No. 11/649,995, filed Jan. 5, 2007, which is acontinuation of U.S. patent application Ser. No. 11/338,090, filed Jan.24, 2006, which is a continuation of U.S. patent application Ser. No.10/946,384, filed Sep. 20, 2004, now U.S. Pat. No. 7,021,764, which is adivisional of U.S. patent application Ser. No. 10/773,667, filed Feb. 6,2004, now U.S. Pat. No. 6,840,619, which is a continuation of U.S.patent application Ser. No. 10/044,304, filed Oct. 25, 2001, now U.S.Pat. No. 6,712,466, all of which are hereby incorporated by reference intheir entireties.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to an eyeglass manufacturingmethod using a layer with a variable index of refraction. Morespecifically, the present invention pertains to patient-specificspectacle lenses manufactured with an variable index aberrator in orderto more accurately correct lower order aberrations and additionallycorrect higher order aberrations. The present invention also provides ameans for correcting vision problems caused by retinal dysfunction.

2. Description of the Related Art

Present manufacturing techniques for eyeglass lenses are capable ofproducing lenses that correct only the lower order (sphere and cylinder)aberrations. Customarily, lens blanks are available in discrete steps ofrefractive power of 0.25 diopters. In most cases, these steps are toolarge to create optimum vision for a patient's eye.

Current manufacturing techniques do not effectively treat visionproblems resulting from retinal dysfunction. For example, in maculardegeneration, patients suffer from vision loss in selective areas of thefundus, typically close to the center of vision. Laser treatment of theaffected areas further destroys retinal tissue, causing blindness at thetreated areas. Clinical studies have shown that the human eye and brainare capable of switching to other areas of the retina to substitute thedamaged area with an undamaged area. In other words, damaged areas inthe retina are essentially bypassed by the brain. Ultimately, visionloss will occur as a portion of an image falls on the damaged retina.Consequently, there is a need to manufacture an eyepiece such that theimage may be “warped” around the dysfunctional tissue in order to allowthe entire image to focus on the remaining healthy tissue.

In light of the aforementioned problems, the need for an optical elementwhich generates a unique wavefront phase profile becomes apparent.Traditional manufacturing methods create such profiles through grindingand polishing. Such a method of manufacture is very costly due to theamount of time and expertise required.

SUMMARY OF THE PRESENT INVENTION

The present invention utilizes the technology developed by the wavefrontaberrator in which a layer of variable index material, such as curableepoxy, can be sandwiched between two plane or curved glass or plasticplates. This sandwich is then exposed to the curing radiation (i.e., UVlight) that is modulated spatially or temporally in order to createspatially resolved variations of refractive indices. This will allow themanufacturing of a lens that is capable of introducing or compensatingfor low and high order aberrations.

In the simplest form, two lens blanks are sandwiched together with alayer of epoxy such that the lenses used in conjunction approximatelycorrect the patient's refractive spherical and cylindrical correction towithin 0.25 diopters. Subsequently, the epoxy aberrator would be exposedto curing radiation in a pre-programmed way in order to fine-tune therefractive properties of the spectacle lens to the exact spherical andcylindrical prescription of the patient's eye.

Another application of the present invention is to manufacturemulti-focal or progressive addition lenses constructed with a layer ofvariable index material sandwiched in between the two lens blanks. Thedrawback of progressive addition lenses today is that, like regularspectacle lenses, a true customization for a patient's eye cannot beachieved due to the current manufacturing techniques. Using the twolenses and epoxy, a customized progressive addition lens or reading lenscan be manufactured by appropriately programming the curing of the epoxyaberrator.

The present invention provides an opportunity to manufacture lenses thatgive patients “supervision.” In order to achieve supervision, higherorder aberrations of the patient's eye need to be corrected. Since thesehigher order aberrations, unlike the spherical and cylindricalrefractive error, are highly asymmetrical, centering of the eye'soptical axis with the zone of higher order correction (“supervisionzone”) is important. To minimize this effect, one could devise aspectacle lens that incorporates a supervision zone only along thecentral optical axis, allowing the patient to achieve supervision forone or more discrete gazing angles. The remainder of the lens would thenbe cured to correct only the lower order aberrations. An optionaltransition zone could be created between the supervision zone and thenormal vision zone allowing for a gradual reduction of higher orderaberrations. Again, all of this would be achieved by spatially resolvedprogramming of the epoxy aberrator's curing.

In order to cover a larger field of view with supervision, a multitudeof supervision “islands” might be created. The supervision islands thenare connected by transition zones that are programmed to graduallychange the higher order aberrations in order to create smoothtransitions.

In bifocal lenses, refractive power in discrete steps of 1 diopter isadded in the lower area of the lens to aid the spectacle wearer in neardistance viewing, i.e. reading. For cosmetic reasons, the visibledividing line between the distance viewing area and the reading area isdisliked by many presbyobic patients. With the event of the progressiveaddition lens, the sharp dividing line between the distance area and thereading area has been eliminated by introducing a continuous varifocalcorridor of vision with a refractive power slowly changing from thedistance viewing prescription to the reading prescription.

However, due to manufacturing limitations several disadvantages existwith the progressive addition lens. First, vision through areas outsidethe corridor is noticeably distorted, making the progressive additionlens unsuitable for many patients. Second, while the patient'sindividual prescription is applied to the distance viewing area, theadded refractive power for the reading area is only offered in discretesteps of 1 diopter. Third, the distance between the centers of thedistance viewing and reading viewing areas is fixed by the lens designand cannot be changed to accommodate for an individual's preference orapplication. Furthermore, the corridor design is fixed for anyparticular brand of lens and cannot be changed according to thepatient's actual viewing preferences or spectacle frame selected.

Therefore, when prescribing a progressive addition lens, the eye careprofessional has to choose from an assortment of designs andmanufacturers of the lens which matches the requirements of the patientmost closely. The present invention allows one to manufacture a lensthat is entirely customized and optimized to the patient's individualrequirements.

Lastly, the present invention may be used to “warp” the retinal image sothat damaged portions of the retina will be bypassed by the image. Inorder to do this, the visual field of the patient needs to be mappedwith a perimeter or micro-perimeter. From this map of healthy retina,spectacle lenses could be manufactured using the epoxy aberrator.

DESCRIPTION OF THE DRAWINGS

The novel features of this invention, as well as the invention itself,both as to its structure and its operation, will be best understood fromthe accompanying drawings, taken in conjunction with the accompanyingdescription, in which like reference characters refer to similar parts,and in which:

FIG. 1 is a perspective view of an eyeglass that incorporates asupervision zone for long distance applications;

FIG. 2 shows a cross sectional view of FIG. 1;

FIG. 3 shows a top view of a progressive addition lens, which includes asupervision zone and reading zone;

FIG. 4 shows a top view of a reading or special application lens;

FIG. 5A shows a top view of a lens including a multitude of supervisionislands, which cover a larger view with supervision;

FIG. 5B shows a top view of a multi-focal lens including a multitude ofreading islands, allowing for far vision correction and simultaneousreading correction;

FIG. 6 shows a text object imaged onto a damaged retina;

FIG. 7 shows the image of the same object as FIG. 6 from the patient'sperspective;

FIG. 8 shows the patient's view of the image after the brain shuts downthe damaged retina;

FIG. 9 shows an image focused on a damaged retina, with a correctivelens in place;

FIG. 10 shows the image as the patient initially sees it;

FIG. 11 shows the image as the patient sees it after the brain shutsdown the damaged retina; and

FIG. 12 shows a sequence of manufacture for the present invention.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

Referring initially to FIG. 1, a lens assembly that incorporates asupervision zone is shown and generally designated 100. FIG. 1 showsthat the lens assembly 100 includes an upper lens 102, a variable indexlayer 103, and a lower lens 104. In a preferred embodiment, the variableindex layer is made of ultra-violet curing epoxy which exhibits an indexof refraction that can be changed by exposure to ultraviolet radiation.However, it is to be appreciated that other materials which exhibitsimilar characteristics, namely a variable index of refraction, may beincorporated into the present invention without departing from thespirit of the invention.

The variable index layer 103 makes up the normal vision zone 106, thetransition zone 110, and the supervision zone 108, where the epoxy ateach zone is cured to a specific index of refraction. The normal visionzone 106 corrects the lower order spherical and cylindrical aberrationsof the patient's eye. The transition zone 110 allows for a gradualreduction of higher order aberrations. The supervision zone 108 liesalong the patient's optical axis (not shown) and corrects the higherorder aberrations allowing the patient to achieve supervision for one ormore discrete gazing angles. The shape of the lens 100 is meant to beexemplary of the shape of a typical eyeglass lens, and any shape,including highly curved lenses, may be used while not departing from thepresent invention.

Referring now to FIG. 2, a cross section of lens 100 is represented suchthat upper lens 102 has a thickness 112, epoxy layer 103 has a thickness116, and the lower lens 104 has a thickness 114. The epoxy layer 103 issandwiched between the upper lens 102 and the lower lens 104 and is heldin place by a stopper 118.

Referring now to FIG. 3, an alternative embodiment of the presentinvention is illustrated as a progressive addition lens and generallydesignated 200. FIG. 3 shows a top view of a transition lens 200 inwhich there is a supervision zone 202, a transition zone 204, and ashort distance viewing zone 206. The normal vision zone 208 of theprogressive addition lens 200 is corrected for the lower aberrations.Again, the creation of the various vision zones is by means ofselectively curing the epoxy aberrator sandwiched between two glass (orplastic) blanks, not through the traditional means of grinding ormolding these features into a blank. The transition lens 200 has asimilar cross section to that depicted in FIG. 2.

Referring now to FIG. 4, another alternative embodiment of the presentinvention is illustrated as a reading lens and generally designated 300.FIG. 4 shows a top view of a reading lens 300 in which there is asupervision zone 302, a transition zone 304, and a normal vision zone306. The reading lens 300 has a similar cross section to that depictedin FIG. 2. The supervision zone 302 may be used for, but not limited to,high-resolution applications such as reading, precision close up work,etc.

Referring now to FIG. 5A, an alternative embodiment of the presentinvention is illustrated as a supervision lens that covers a largerfield of view and is generally designated 400. FIG. 5A shows a top viewof a supervision lens 400 in which there is a plurality of supervisionislands 402, and a transition zone 404. The plurality of supervisionislands 402 create a larger field of view for the patient, while thetransition zone 404 is manufactured to gradually change the higher orderaberrations in order to create smooth transitions.

Referring now to FIG. 5B, another alternative embodiment of the presentinvention is illustrated as a multi-focal lens that allows forsimultaneous correction for far vision and reading vision and isgenerally designated 450. FIG. 5B shows a top view of a multi-focal lens450 in which there is a plurality of optical islands 452, eachrepresenting the patient's reading prescription while the backgroundzone 454 represents the patient's far vision prescription, or viceversa. Ideally, the diameter of the optical islands is on the order of100 microns so that a maximum number of optical islands falls within thetypical pupil size of 2 to 6 mm diameter.

One special application of this invention is the use for correctingvision problems caused by retinal dysfunction, e.g., by eye diseaseslike glaucoma or macular degeneration. FIG. 6 shows an eye generallydesignated 500, in which an image 502 is imaged by the eye's cornea andlens 504 onto the inner surface of the eye 500 where there is damagedretinal tissue 506. The patient initially sees only a portion of theimage and an obstruction, as shown in FIG. 7. Eventually the brain shutsoff the damaged portion of the retina and the patient's view no longerincludes the obstruction, such a view is represented in FIG. 8. Althoughthe patient no longer sees an obstruction, a portion of the imageremains unseen. The present invention is capable of correcting thisphenomenon as illustrated in FIGS. 9-11. FIG. 9 again shows an eyegenerally designated 600, in which an object 602 is imaged through theeye's cornea and lens 604 onto the inner surface of the eye 600 wherethere is damaged retinal tissue 606. However, a lens 608 manufacturedusing the epoxy wavefront aberrator is placed in front of the eye 600.The retinal image 609 of the object 602 is warped around damaged retinaltissue 606 such that none of the image 602 is lost. FIG. 10 shows theimage the patient sees. As previously mentioned, over time the brainwill terminate the signals generated by the damaged retinal tissue 606and the patient will see the entire image 602 as shown in FIG. 11.

FIG. 12 shows a flow chart in which the manufacturing steps of thepresent invention are disclosed and generally designated 700. First thepatient's eye must be imaged in order to determine the wavefrontprescription. Second, both the upper and lower lenses must be selected.This selection corrects both the patient's spherical and cylindricalaberrations to within 0.25 diopters. Next, one side of the first lens iscoated with epoxy. The second lens in then placed on the epoxy coatedsurface of the first lens, such that the epoxy is sandwiched between thetwo lenses. Finally the epoxy is cured to match the wavefrontprescription.

While the different embodiments of the present invention as herein shownand disclosed in detail is fully capable of obtaining the objects andproviding the advantages herein before stated, it is to be understoodthat it is merely illustrative of a preferred embodiment and analternative embodiment of the invention and that no limitations areintended to the details of construction or design herein shown otherthan as described in the appended claims.

1. A method of treating a person with retinal dysfunction whichcomprises providing the patient with spectacle lenses that correct forlow order aberrations and at least one high order aberration.
 2. Themethod of claim 1 wherein retinal dysfunction is macular degenerationand the spectacle lenses comprise a layer of a curable material that hasbeen cured to provide a layer having a variable refractive index whichcorrects the at least one high order aberration.
 3. The method of claim1 wherein the curable material is an epoxy.
 4. The method of claim 4wherein the epoxy is cured by exposure to ultraviolet radiation.
 5. Aretinal dysfunction-correcting spectacle lens which comprises a loworder aberration-correcting lens and a layer of a curable material thathas been cured to provide a layer of variable refractive index whichcorrects at least one high order aberration and said high orderaberration correction provides improved vision to a person with theretinal dysfunction.
 6. The spectacle lens of claim 5 wherein theretinal dysfunction is macular degeneration.
 7. The spectacle lenses ofclaim 6 wherein the curable material is an epoxy.
 8. The spectacle lensof claim 7 wherein the epoxy is cured by exposure to ultravioletradiation.